1. Field of the Invention
This invention relates in general to a method and apparatus for processing audio/video information, and more particularly to a method and apparatus for providing stream linking in audio/video disk media.
2. Description of Related Art
Advancements in communications technology and increased consumer sophistication have challenged the distributors of multimedia programming to provide the subscribing public with entertainment services more convenient and accessible than those traditionally made available over cable television and telephone systems. An improving communications infrastructure has resulted in a proliferation of pay-per-view media services in many of the larger broadcast markets. Most pay-per-view systems permit the consumer to choose from a relatively small number of motion picture selections for home viewing, with the selected programs generally being presented only at pre-scheduled viewing times.
In recent years, the media industry has expanded its horizons beyond traditional analog technologies. Audio, photographs, and even feature films are now being recorded or converted into digital formats. To encourage compatibility between products, standard formats have been developed in many of the media categories.
As would be expected, the viewers of digital video desire the same functionality from the providers of digital video as they now enjoy while watching analog video tapes on video cassette recorders. For example, viewers want to be able to make the video jump ahead, jump back, fast forward, fast rewind, slow forward, slow rewind and freeze frame.
Various approaches have been developed to provide non-sequential playback of digital video data. With respect to digital video data, non-sequential playback refers to any playback operation that does not play all of the encoded frames in the exact order in the sequence in which they were encoded. For example, jump ahead and fast forward operations are non-sequential in that some frames are skipped. Rewind operations at any speed are non-sequential in that during a rewind operation, frames are not played in the sequence in which they are encoded.
Data used for Audio/Video (AV) applications is typically stored in contiguous areas on disk drives and accessed sequentially. Computer systems access disk drives by logical block number. For digital Audio/Video applications it is useful to refer to the data structure for disk drives as a stream. A stream is a range of addresses on the disk media in which a contiguous area of Audio/Video data is stored. AV applications stream data on and off disk drives by writing contiguous blocks, which are typically linear streams of data.
The ATA (Advanced Technology Attachment) Interface is the dominant storage interface for personal computers. ATA was originally defined as a standard for embedded fixed disk storage on IBM AT™ compatible personal computers. AT™ stands for “Advanced Technology”, which refers primarily to it's then “revolutionary” 16-bit bus. In recent years ATA-3 and ATA-4 have enhanced the functionality of the ATA interface to increase performance and interface a wider range of personal computer storage devices.
The ATA command set is designed for random access to blocks of data. The design of Audio/Video products which use ATA hard disk drives would be simplified by providing a stream oriented AV command system. In a system for addressing Audio/Video (AV) data using contiguous areas called streams, it may be useful to quickly set up additional reading or writing locations in streams that have been previously established. An easy way to do this is to have a linked stream capability.
It can be seen then that there is a need for a method and apparatus that provides stream linking in audio/video disk media.